Seven drug-free patients with bipolar affective disorder, currently in a
manic phase, underwent desipramine-induced growth hormone (GH) stimulation,
as did seven healthy age- and sex-matched subjects. There was significant
blunting of GH release in the manic patients, suggesting a down-regulation
of alpha 2-noradrenergic responses. Blunting of GH release was not related
to severity of symptoms, duration of illness, or age. Similar blunting has
previously been described in depressed patients.